package com.github.llyb120.crypt.zuc;

/**
 * Created by 34494 on 2018/9/7.
 */
public class ZUC {
    /* state registers LFSR */
    private static int[] LFSR_S = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

    /* F registers */
    private static int F_R1 = 0;
    private static int F_R2 = 0;

    /* output of BR procedure */
    private static int[] BRC_X = {0,0,0,0};

    /* S-boxes */
    private static int[] S0 = {
            0x3e, 0x72, 0x5b, 0x47, 0xca, 0xe0, 0x00, 0x33, 0x04, 0xd1, 0x54, 0x98, 0x09, 0xb9, 0x6d, 0xcb,
            0x7b, 0x1b, 0xf9, 0x32, 0xaf, 0x9d, 0x6a, 0xa5, 0xb8, 0x2d, 0xfc, 0x1d, 0x08, 0x53, 0x03, 0x90,
            0x4d, 0x4e, 0x84, 0x99, 0xe4, 0xce, 0xd9, 0x91, 0xdd, 0xb6, 0x85, 0x48, 0x8b, 0x29, 0x6e, 0xac,
            0xcd, 0xc1, 0xf8, 0x1e, 0x73, 0x43, 0x69, 0xc6, 0xb5, 0xbd, 0xfd, 0x39, 0x63, 0x20, 0xd4, 0x38,
            0x76, 0x7d, 0xb2, 0xa7, 0xcf, 0xed, 0x57, 0xc5, 0xf3, 0x2c, 0xbb, 0x14, 0x21, 0x06, 0x55, 0x9b,
            0xe3, 0xef, 0x5e, 0x31, 0x4f, 0x7f, 0x5a, 0xa4, 0x0d, 0x82, 0x51, 0x49, 0x5f, 0xba, 0x58, 0x1c,
            0x4a, 0x16, 0xd5, 0x17, 0xa8, 0x92, 0x24, 0x1f, 0x8c, 0xff, 0xd8, 0xae, 0x2e, 0x01, 0xd3, 0xad,
            0x3b, 0x4b, 0xda, 0x46, 0xeb, 0xc9, 0xde, 0x9a, 0x8f, 0x87, 0xd7, 0x3a, 0x80, 0x6f, 0x2f, 0xc8,
            0xb1, 0xb4, 0x37, 0xf7, 0x0a, 0x22, 0x13, 0x28, 0x7c, 0xcc, 0x3c, 0x89, 0xc7, 0xc3, 0x96, 0x56,
            0x07, 0xbf, 0x7e, 0xf0, 0x0b, 0x2b, 0x97, 0x52, 0x35, 0x41, 0x79, 0x61, 0xa6, 0x4c, 0x10, 0xfe,
            0xbc, 0x26, 0x95, 0x88, 0x8a, 0xb0, 0xa3, 0xfb, 0xc0, 0x18, 0x94, 0xf2, 0xe1, 0xe5, 0xe9, 0x5d,
            0xd0, 0xdc, 0x11, 0x66, 0x64, 0x5c, 0xec, 0x59, 0x42, 0x75, 0x12, 0xf5, 0x74, 0x9c, 0xaa, 0x23,
            0x0e, 0x86, 0xab, 0xbe, 0x2a, 0x02, 0xe7, 0x67, 0xe6, 0x44, 0xa2, 0x6c, 0xc2, 0x93, 0x9f, 0xf1,
            0xf6, 0xfa, 0x36, 0xd2, 0x50, 0x68, 0x9e, 0x62, 0x71, 0x15, 0x3d, 0xd6, 0x40, 0xc4, 0xe2, 0x0f,
            0x8e, 0x83, 0x77, 0x6b, 0x25, 0x05, 0x3f, 0x0c, 0x30, 0xea, 0x70, 0xb7, 0xa1, 0xe8, 0xa9, 0x65,
            0x8d, 0x27, 0x1a, 0xdb, 0x81, 0xb3, 0xa0, 0xf4, 0x45, 0x7a, 0x19, 0xdf, 0xee, 0x78, 0x34, 0x60
    };

    private static int[] S1 = {
            0x55, 0xc2, 0x63, 0x71, 0x3b, 0xc8, 0x47, 0x86, 0x9f, 0x3c, 0xda, 0x5b, 0x29, 0xaa, 0xfd, 0x77,
            0x8c, 0xc5, 0x94, 0x0c, 0xa6, 0x1a, 0x13, 0x00, 0xe3, 0xa8, 0x16, 0x72, 0x40, 0xf9, 0xf8, 0x42,
            0x44, 0x26, 0x68, 0x96, 0x81, 0xd9, 0x45, 0x3e, 0x10, 0x76, 0xc6, 0xa7, 0x8b, 0x39, 0x43, 0xe1,
            0x3a, 0xb5, 0x56, 0x2a, 0xc0, 0x6d, 0xb3, 0x05, 0x22, 0x66, 0xbf, 0xdc, 0x0b, 0xfa, 0x62, 0x48,
            0xdd, 0x20, 0x11, 0x06, 0x36, 0xc9, 0xc1, 0xcf, 0xf6, 0x27, 0x52, 0xbb, 0x69, 0xf5, 0xd4, 0x87,
            0x7f, 0x84, 0x4c, 0xd2, 0x9c, 0x57, 0xa4, 0xbc, 0x4f, 0x9a, 0xdf, 0xfe, 0xd6, 0x8d, 0x7a, 0xeb,
            0x2b, 0x53, 0xd8, 0x5c, 0xa1, 0x14, 0x17, 0xfb, 0x23, 0xd5, 0x7d, 0x30, 0x67, 0x73, 0x08, 0x09,
            0xee, 0xb7, 0x70, 0x3f, 0x61, 0xb2, 0x19, 0x8e, 0x4e, 0xe5, 0x4b, 0x93, 0x8f, 0x5d, 0xdb, 0xa9,
            0xad, 0xf1, 0xae, 0x2e, 0xcb, 0x0d, 0xfc, 0xf4, 0x2d, 0x46, 0x6e, 0x1d, 0x97, 0xe8, 0xd1, 0xe9,
            0x4d, 0x37, 0xa5, 0x75, 0x5e, 0x83, 0x9e, 0xab, 0x82, 0x9d, 0xb9, 0x1c, 0xe0, 0xcd, 0x49, 0x89,
            0x01, 0xb6, 0xbd, 0x58, 0x24, 0xa2, 0x5f, 0x38, 0x78, 0x99, 0x15, 0x90, 0x50, 0xb8, 0x95, 0xe4,
            0xd0, 0x91, 0xc7, 0xce, 0xed, 0x0f, 0xb4, 0x6f, 0xa0, 0xcc, 0xf0, 0x02, 0x4a, 0x79, 0xc3, 0xde,
            0xa3, 0xef, 0xea, 0x51, 0xe6, 0x6b, 0x18, 0xec, 0x1b, 0x2c, 0x80, 0xf7, 0x74, 0xe7, 0xff, 0x21,
            0x5a, 0x6a, 0x54, 0x1e, 0x41, 0x31, 0x92, 0x35, 0xc4, 0x33, 0x07, 0x0a, 0xba, 0x7e, 0x0e, 0x34,
            0x88, 0xb1, 0x98, 0x7c, 0xf3, 0x3d, 0x60, 0x6c, 0x7b, 0xca, 0xd3, 0x1f, 0x32, 0x65, 0x04, 0x28,
            0x64, 0xbe, 0x85, 0x9b, 0x2f, 0x59, 0x8a, 0xd7, 0xb0, 0x25, 0xac, 0xaf, 0x12, 0x03, 0xe2, 0xf2
    };

    /* D constants */
    private static int[] EK_d = {
            0x44D7, 0x26BC, 0x626B, 0x135E, 0x5789, 0x35E2, 0x7135, 0x09AF,
            0x4D78, 0x2F13, 0x6BC4, 0x1AF1, 0x5E26, 0x3C4D, 0x789A, 0x47AC
    };

    private static int AddM(int a, int b) {
        int c = a + b;
        return (c & 0x7FFFFFFF) + ((c & 0x80000000) >>> 31);
    }

    private static int MulByPow2(int x, int k) {
        return ((((x) << k) | ((x) >>> (31 - k))) & 0x7FFFFFFF);
    }

    /* LFSR */
    private static void LFSRWithInitializationMode(int u) {
        int f, v;

        f = LFSR_S[0];
        v = MulByPow2(LFSR_S[0], 8);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[4], 20);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[10], 21);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[13], 17);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[15], 15);
        f = AddM(f, v);

        f = AddM(f, u);

        /* update the state */
        for (int i = 0; i < 15; ++i) {
            LFSR_S[i] = LFSR_S[i + 1];
        }
        LFSR_S[15] = f;
    }

    /* LFSR with work mode */
    private static void LFSRWithWorkMode() {
        int f, v;

        f = LFSR_S[0];
        v = MulByPow2(LFSR_S[0], 8);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[4], 20);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[10], 21);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[13], 17);
        f = AddM(f, v);

        v = MulByPow2(LFSR_S[15], 15);
        f = AddM(f, v);

        /* update state */
        for (int i = 0; i < 15; ++i) {
            LFSR_S[i] = LFSR_S[i + 1];
        }
        LFSR_S[15] = f;
    }

    /* Bit Reorganization Procedure */
    private static void BitReorganization() {
        BRC_X[0] = ((LFSR_S[15] & 0x7FFF8000) << 1) | (LFSR_S[14] & 0xFFFF);
        BRC_X[1] = ((LFSR_S[11] & 0xFFFF) << 16) | (LFSR_S[9] >>> 15);
        BRC_X[2] = ((LFSR_S[7] & 0xFFFF) << 16) | (LFSR_S[5] >>> 15);
        BRC_X[3] = ((LFSR_S[2] & 0xFFFF) << 16) | (LFSR_S[0] >>> 15);
    }

    private static long ROT(long a, int k) {
        return (((a) << k) | ((a) >>> (32 - k)));
    }

    /* linear transformation L1 */
    private static long L1(long X) {
        return (X ^ ROT(X, 2) ^ ROT(X, 10) ^ ROT(X, 18) ^ ROT(X, 24));
    }

    /* linear transformation L2 */
    private static long L2(long X) {
        return (X ^ ROT(X, 8) ^ ROT(X, 14) ^ ROT(X, 22) ^ ROT(X, 30));
    }

    /* create 32-bit word */

    private static int MAKEU32(int a, int b, int c, int d) {
        return (int) (((long) a << 24) | ((long) b << 16) | ((long) c << 8) | ((long) d));
    }

    /* non-linear function F */
    private static long F() {
        long W, W1, W2, u, v;

        W = (BRC_X[0] ^ F_R1) + F_R2;
        W = W & 0x00000000FFFFFFFFL;
        W1 = F_R1 + BRC_X[1];
        W1 = W1 & 0x00000000FFFFFFFFL;
        W2 = F_R2 ^ BRC_X[2];
        W2 = W2 & 0x00000000FFFFFFFFL;
        u = L1((W1 << 16) & 0x00000000FFFFFFFFL | (W2 >>> 16));
        u = u & 0x00000000FFFFFFFFL;
        v = L2((W2 << 16) & 0x00000000FFFFFFFFL | (W1 >>> 16));
        v = v & 0x00000000FFFFFFFFL;
        F_R1 = MAKEU32(S0[(int) (u >>> 24)], S1[(int) ((u >>> 16) & 0xFF)], S0[(int) ((u >>> 8) & 0xFF)], S1[(int) (u & 0xFF)]);
        F_R2 = MAKEU32(S0[(int) (v >>> 24)], S1[(int) ((v >>> 16) & 0xFF)], S0[(int) ((v >>> 8) & 0xFF)], S1[(int) (v & 0xFF)]);

        return W;
    }

    private static int MAKEU31(int a, int b, int c) {
        return (int) (((long) ((long) (0)
                | (int) (a)) << 23)
                | ((long) (b) << 8)
                | (long) ((long) (0)
                | (int) (c)));
    }

    public static void Initialization(int[] k, int[] iv) {
        long w;

        /* expand key */
        for (int i = 0; i < 16; ++i) {
            LFSR_S[i] = MAKEU31(k[i], EK_d[i], iv[i]);
        }

        long nCount = 32;
        while (nCount > 0) {
            BitReorganization();
            w = F();
            LFSRWithInitializationMode((int) (w >>> 1));
            nCount--;
        }

        BitReorganization();
        F();
        LFSRWithWorkMode();
    }

    public static void GenerateKeyStream(long[] pKeyStream, long KeyStreamLen) {
        /* working cycles */
        for (int i = 0; i < KeyStreamLen; ++i) {
            BitReorganization();
            pKeyStream[i] = F() ^ BRC_X[3] & 0x00000000ffffffffL;
            LFSRWithWorkMode();
        }
    }
}